Feature Comparison · 2026

Agentis vs Custom Checkout App

Quick Verdict

Custom Checkout App is a custom-built checkout modification apps developed by agencies or in-house teams tool. Agentis works after an order is placed and before it ships: within 60 seconds it computes the order's true net margin from NetSuite COGS, freight, fees, and FX, then flags it or holds it before fulfillment under rules you approve. They solve different problems and often run side by side.

By Herzel MishelFounder, AgentisLast reviewed October 2, 2026

The Core Difference

Custom Checkout App excels at custom-built checkout modification apps developed by agencies or in-house teams. That is its job, and the strengths and limitations below are judged on margin protection only, not on everything the product does.

Agentis sits at a specific point in the order lifecycle: between order placed and order shipped. Within 60 seconds of each order on your Shopify, Shopify Plus, or SHOPLINE store, it computes true net margin using live COGS from Oracle NetSuite plus freight, fees, and FX. Orders below your margin floor are flagged with the leak and a recommended fix, or automatically held before fulfillment under rules you approve, and every decision is logged to the Evidence Ledger.

The result: you catch a below-margin order while it can still be fixed, instead of finding it at month-end close.

Feature-by-Feature Comparison

Feature	Agentis	Custom Checkout App
True net margin on every order (COGS, freight, fees, FX)
COGS tracking
Margin alerts
Shopify Plus integration
NetSuite / ERP integration
Freight cost modeling
FX rate adjustment
Holds below-margin orders before they ship
Profit dashboard
Ad attribution
LTV analytics

Why choose Agentis

Computes true net margin on every order within 60 seconds of it being placed
Holds below-margin orders before fulfillment under rules you approve, or flags them with a recommended fix
Uses live COGS from Oracle NetSuite (commonly via Celigo)
Includes freight, payment fees, and FX in each order's margin
Works after the order is placed, so the shopper's checkout is untouched
Works with Shopify, Shopify Plus, and SHOPLINE, and logs every decision to an Evidence Ledger

When to choose Custom Checkout App

A custom checkout app makes sense when your logic is truly unique, for example a marketplace with per-vendor commission structures, or a regulated vertical where no off-the-shelf app can satisfy your compliance posture, and when the rule genuinely has to run inside checkout. Agentis is a different design, not a cheaper version of the same one: it does not run in checkout at all. After each order is placed and before it ships, it computes true net margin from live NetSuite COGS, freight, fees, and FX within 60 seconds, and flags the order or holds it before fulfillment under rules you approve. That avoids the Functions execution limits and the per-release maintenance a checkout build carries, at the cost of not changing what the shopper sees. If what you need is to stop below-margin orders from shipping rather than to change the checkout itself, model a custom build's three-year cost (build, maintenance, developer continuity, Shopify platform changes) against a per-order margin layer before committing.

Custom Checkout App Strengths

Full customization: every rule in a custom checkout app can be tailored to exact business logic
No vendor dependency or ongoing SaaS subscription for your custom Shopify app
Can integrate with any internal system, ERP, or data warehouse
Intellectual property stays entirely in-house
Suitable when your build vs buy Shopify checkout analysis shows genuinely unique requirements no vendor addresses

Honest Assessment

Where Custom Checkout App falls short for margin protection

$50K–$150K initial build cost for a custom checkout app with 3–6 month delivery timeline
Requires an ongoing maintenance team or retainer for updates and bug fixes to the custom Shopify app
No built-in COGS sync, freight zone modeling, or FX rate engine: all must be built from scratch
Breaks on Shopify platform updates (Checkout Extensibility, Functions API changes)
Single point of failure if the lead developer or agency relationship ends
Shopify Functions enforce strict execution limits (instruction count, input size, no general network access) that data-heavy custom margin logic frequently runs into
Most build vs buy Shopify checkout decisions underestimate the compliance burden of PCI scope, SOC 2 evidence, and quarterly Shopify platform certifications

Frequently Asked Questions

How does the total cost of ownership compare between a custom app and Agentis?

A custom checkout app typically costs $50K–$150K to build and $24K–$60K per year to maintain, putting three-year TCO at $120K–$330K. The maintenance figure is not optional: a custom checkout app requires an ongoing maintenance team or retainer for updates and bug fixes, and it breaks on Shopify platform updates such as Checkout Extensibility and Functions API changes. The build also has to include COGS sync, freight zone modeling, and an FX rate engine from scratch, since none of that exists out of the box. Agentis has no custom build: it connects to your store and NetSuite and checks each order after it is placed, so there is no checkout code for your team to maintain. Agentis pricing is quoted through sales rather than published, so get a quote and put it in the same three-year model. A custom build still makes sense when the logic is genuinely unique and has to run inside checkout. Otherwise, model the decision over three years, including developer turnover and platform compatibility, before committing to a build.

Can I migrate from a custom checkout app to Agentis?

Yes, with one design difference to plan for. A custom checkout app runs inside checkout; Agentis runs after the order is placed and before it ships, computing each order's true net margin within 60 seconds and flagging or holding it under rules you approve. Margin rules such as COGS floors, freight-aware thresholds, and FX-aware checks can be expressed as Agentis rules, and you can run both systems in parallel for a period, comparing which orders each one would catch, before decommissioning the custom app. The migration removes the ongoing maintenance team or retainer a custom checkout app requires and the exposure to breakage when Shopify ships Checkout Extensibility or Functions API changes. It also removes the single point of failure of one lead developer or agency. Logic that must change the checkout itself, or genuinely unique structures like per-vendor commissions in a marketplace, may still belong in a custom build.

How do Shopify Functions CPU limits affect custom checkout apps?

Shopify Functions run in a sandbox with strict execution limits: a capped instruction budget, limited input size, and no general network access during execution. Custom apps that perform complex margin calculations, especially those involving live COGS lookups, freight zone resolution, or FX conversion, frequently hit these ceilings, because those are separate lookups that all have to fit inside the same execution window. Builds that exceed the limits either fail at checkout or force the team to strip out the very checks that make the logic meaningful, and Functions API changes can shift what fits over time. Agentis is not subject to these limits because it does not run inside checkout: it evaluates each order after it is placed, where it can read NetSuite COGS, freight, fees, and FX directly, and it acts by flagging or holding the order before fulfillment. The trade-off is that it cannot change the cart in front of the shopper. A merchant evaluating a custom build should ask the developer to demonstrate the full evaluation running within the limits on real cart sizes before committing.

What happens to my custom app when the original developer leaves?

This is the most common failure mode for custom checkout apps. When the lead developer or agency moves on, you inherit undocumented code that new engineers must reverse-engineer, often under time pressure when Shopify ships a breaking platform update. The exposure is compounded by the fact that a custom checkout app requires an ongoing maintenance team or retainer, so losing the original developer means finding and funding a replacement while the app keeps running in production. With Agentis there is no checkout code of yours to inherit: the margin rules live in Agentis, the product is maintained by the Agentis team, and because it works on orders after checkout, Shopify checkout changes do not require you to rewrite anything. When weighing build vs buy, treat developer continuity as a line item alongside the initial build cost, not as an afterthought.

How should finance teams frame the build vs buy Shopify checkout decision?

Treat the build vs buy question as a three-year TCO model, not a Year One budget line. Building a custom checkout app looks cheaper on paper until you amortize discovery, QA, Shopify Plus certification, security and compliance evidence gathering, and the engineers you will need on permanent rotation to keep pace with Shopify Functions and Checkout Extensibility changes. Buying converts that capex-plus-opex profile into a predictable subscription. Finance teams should also be clear about what each option does: a custom checkout app can change the cart before the order is placed, while Agentis checks each order's true net margin after it is placed and flags or holds below-margin orders before they ship. If the goal is to stop losing money on individual orders, the second is often enough; if the checkout itself must behave differently, it is not. Put differently, the cost of the build is not the build itself; it is the ongoing maintenance, platform compatibility, and developer continuity required to keep it running.